U.S. Pat. Nos. 7,989,473 and 8,178,127 disclose stable preparations of N-ethyl-N-phenyl-1,2-dihydro-4-hydroxy-5-chloro-1-methyl-2-oxoquinoline-3-carboxamide (CAS Number 248281-84-7), also known as laquinimod (laq.). Laquinimod has been shown in U.S. Pat. No. 6,077,851 to be effective in the acute experimental autoimmune encephalomyelitis (aEAE) model. U.S. Pat. No. 6,077,851 discloses the synthesis of laquinimod and the preparation of its sodium salt. U.S. Pat. No. 6,875,869 discloses an additional synthesis process of laquinimod.
PCT International Application Publication No. WO 2005/074899 discloses pharmaceutical compositions comprising laquinimod sodium.
U.S. Pat. No. 7,589,208 discloses the aqueous solubility of Li, Na, Ca, Cu, Zn, Fe and Mn salts of laquinimod and the experimental preparation of Na, Ca, Fe(III), Li and Zn salts of laquinimod.